The present invention relates to a semiconductor device and a method of manufacturing the semiconductor device. For example, the invention can be used for manufacturing of a semiconductor device including a nonvolatile memory.
An electrically erasable and programmable read only memory (EEPROM) is widely used as an electrically writable and erasable nonvolatile semiconductor storage device. Such a storage device includes a conductive floating gate electrode surrounded by an oxide film or a trapping insulating film below a gate electrode of MISFET, and reads storage information as a threshold of a transistor while assuming a charge accumulating state at the floating gate or the trapping insulating film as the storage information.
The trapping insulating film refers to a charge-accumulable insulating film, and exemplarily includes a silicon nitride film. A threshold of the MISFET is shifted by injecting and emitting charge into/from such a charge accumulating region to allow the MISFET to operate as a storage device. The nonvolatile semiconductor storage device using the trapping insulating film includes a single-gate cell using a metal oxide nitride oxide semiconductor (MONOS).
Japanese Unexamined Patent Application Publication No. 2004-282083 describes that a memory cell having a wedge-shaped oxide nitride oxide (ONO) film, part of which protrudes outward compared with a sidewall of a gate electrode, is provided below the gate electrode.
Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2009-501449 describes a silicon oxide nitride oxide semiconductor (SONOS) nonvolatile memory device, in which a control gate electrode having a width narrower than a stacked film is formed on the stacked film, the stacked film including a tunnel layer, a trap layer, and a charge blocking layer formed in this order on a substrate.